1. Field of the Invention
The present invention relates, in general, to air vents for vehicles and, more particularly, to a technique relating to an air vent for a vehicle, which can increase a duct sealing force, thereby minimizing the amount of air leaking from the duct and yet preventing the air from generating a whistling noise.
2. Description of Related Art
As shown in FIG. 1, a dashboard 1 of a vehicle is typically provided with an air vent 2 for discharging cool or hot air into a passenger compartment.
A conventional air vent 2 includes a duct 2a that guides air into a passenger compartment, a plurality of inside wings 2b that can be rotated so as to switch the direction air is discharged in between the left and right, a plurality of outside wings 2c that can be rotated so as to switch the direction air is discharged in between up and down, and a tab 2d that allows a user to rotate the inside and outside wings 2b and 2c and thereby to change the directions of the inside and outside wings 2b and 2c. 
The inside wings 2b can be rotated to the left and right around respective hinges provided in the upper and lower ends thereof and are called “vertical wings” The outside wings 2c can be rotated upwards and downwards around respective hinges provided in the left and right ends thereof and are called “horizontal wings”.
The tab 2d is connected to the inside wings 2b and to the outside wings 2c so that, when a user moves the tab 2d to the left or right, the tab 2d can be moved along an outside wing 2c and rotate the inside wings 2b in the same direction. however, when a user moves the tab 2d upwards or downwards, the tab 2d can move only the outside wings 2c in the same direction.
Here, the inside wings 2b also function to close the duct 2a to prevent air from being discharged into the passenger compartment.
However, even when the inside wings 2b close the duct 2a, the inside wings 2b cannot completely close the duct 2a because a space allowing the inside wings 2b to be rotated without interference must be provided. Accordingly, the conventional air vent is problematic in that, even when the inside wings 2b close the duct 2a, a substantial amount of air may leak into the passenger compartment through the space provided for the rotation of the inside wings.
In the related art, in an effort to overcome the above-mentioned problem, an air vent structure capable of increasing the duct sealing force so as to desirably seal the duct 2a when the inside wings 2b close the duct 2a has been proposed. However, when the air vent is configured to increase the duct sealing force as described above, the inner pressure of the duct 2a may be increased, so that a substantial level of whistling noise may be generated along the path of passing air.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.